# What is the mass (in grams) of a sample of SO2 with a volume of 118 mL at a pressure of 0.834 atm and at -53°C?

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Expert Answers

mlsiasebs | Certified Educator

Since SO2 is a gas, we can use the ideal gas law to find the answer. The ideal gas equation is

PV = nRT

We are given pressure, volume, and temperature and know R since it is a constant, the only thing we don't know is n (moles). If we find the moles of gas, we can use the molar mass to find the mass of the gas sample.

The first thing to do is to convert the given values to the appropriate units (pressure in atm, volume in L, temperature in K)

118 mL (1 L / 1000 mL) = 0.118 L

-53 degC + 273 = 220 K

Now, we can plug in the values that we know

0.834 atm(0.118 L) = n (0.08206 L atm/molK)(220K)

n = 0.00545 mol SO2

Given the molar mass of SO2 is 64.0 g/mol, we can find the grams of SO2

0.00545 mol (64.0 g/mol) = 0.349 g SO2